Straw-burning furnace.



A. G. JOHNSON. STRAW BURNING PURNAGB. APPLICATION FILED APR. 12, 1909.

Patented May 3, w10.

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A. G. JOHNSON.

STRAW BURNING PURNGE.

APPLICATION FILED APR.12,1909.

Patented May 3, 1910.

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A. G. lJOHNSON.v STRAW BURNING FURNAGB. APPLICATION FILED APR.12,1 909.l

Patented May 3, 1910.v

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ANDREW G. JOHNSON, OF SUTTON, NEBRASKA.

STRAW-BURNING FUR/NACE.

Specification of Letters Patent.

Patented May 3, 31919.

Application filed April 12, 1909. Serial No. 489,272.

T o all whom it may concern:

Be it known that I, ANDREW G. JOHNSON, a citizen of the United States,residing at Sutton, in the county of Clay and State of Nebraska, haveinvented certain new and useful Improvements in Straw Burning Furnaces,of which the following is a specilication.

This invention relates to improvements in straw-burning furnaces of theclass especially adapted for use in connection with traction engines.

The obj ect is to provide means for moving 'or agitating the straw whileburning in the furnace, as an aid to combustion.

Another object is to provide a movable ash rake, useful for removingashes from the furnace, and which by reason of its location andarrangement of parts, operates to materially assist combustion.

The invention also has reference to the form and arrangement of thegrate and to certain operating devices found useful, and to aconstruction embodying as few parts as is consistent with reliableoperation, so that manufacture may be economical.

With these and other objects in view, the invention consists of a novelcombination and arrangement of parts as described herein, pointed out bythe appended claims and as illustrated in the accompanying drawing, itbeing understood that changes in the form, proportion, size and minordetails may be made within the scope of the claims without departingfrom the spirit or sacricing any of the advantages of the invention.

In the drawing, Figure 1 is a vertical, side view showing the body of atraction engine, parts being in section to clearly show construction ofthe furnace. Fig. 2 is a view sectioned on line a a of Fig. 3, showingthe reverse side of the furnace, one of the supporting-bars being partlyvbroken away. Fig. 3 is a plan View, on line 5 l) of Fig. 2, theplatform being partly removed.

Referring now to the drawing for a more particular description, numeral1 indicates a traction engine having a boiler 2, fire-box 3, smoke-stack4 and provided with draftflues 5 providing communication between thefire-box and smoke stack. Within the fireboX, at 6, is shown an arch fordeflecting, in a forward direction, the movement of the flames ofburning material, the opening for the intake of fuel being indicated at7.

While the hereinafter described devices are particularly useful inconnection with traction engines, they may of course be used uponfurnaces generally, where it is desired to employ straw or likematerial, as fuel.

I provide grate bars 3, preferably mounted in pairs, as pairs 9, 10 and11, best shown in Fig. 3; they are disposed parallel with reference toeach other, longitudinally of the fire-box, their front ends beingmounted upon crank shaft 12, their rear ends having mountings upon crankshaft 13, these shafts having their ends mounted at 14, uponsupporting-bars 15. Grate-bars 8 preferably have projections 16 formedto eXtend upwardly at intervals upon their upper edges, theseprojections operating to control the movement of the straw, as will behereinafter explained. Bars 15 are disposed hori- Zontally near thelower part of the fire box at an altitude somewhat lower than the fuelopening, and have front portions 17 inclined upwardly for a supportthereon of feeding-apron 18. As thus described, straw or similarmaterial may be passed through the opening 7 upon the grate bars, and itwill be understood that a movement of shafts 12 and 13 or either of themwill cause a movement of the fuel. Since I employ three pairs ofgrate-bars, the cranks are disposed upon their respective shafts 12 and13, intermediate arcs of 120 degrees, and therefore if a shaft movementis provided as mentioned, a movement for the bed of fuel will beprovided, the preferred movement to be presently explained.

In order to provide a movement of the grate bars, rear shaft 13 ismounted as an idler, and upon front shaft 12 is loosely mountedcrank-arm 19; upon shaft 12 is rigidly mounted ratchet 20, also having aseating adjacent arm 19, and upon said crank-arm is mounted the pawl 21,adapted to engage the ratchet.

At 22 is shown a horizontal shaft to be actuated from any suitablesource of power, applied to pulley 23. Secured upon shaft 22 is thecrank-arm 24 having the rod 24 mounted thereon at 25, this rod alsohaving a pivotal mounting at 26 upon crank-arm 19, and a rotation shaft22 in either direction will cause a swinging movement of arm 19. Pawl 21will thereby cause shaft 12 to be partly rotated at each rotation ofshaft 22, since ratchet 2O is rigidly mounted upon said shaft.

Each grate-bar 8 is mounted at 26 upon crank-shafts 12 and 13, saidshafts being revoluble in these mountings. It will thus be seen thatwhen the grate-bars are at their highest altitude, they are movinglongitudinally toward the rear of the furnace, and this is a desiredfeature so that the straw will be carried rearwardly beneath arch 6while burning. Since both of the bars of each pair are connected to thesame crank upon the crank shaft 18, it follows that the movements of thebars comprising a pair will be in unison, but since the several cranksof the crank shaft 12 are set at an angle of 120O to each other, itfollows that the movement of the pairs of bars with relation to eachother will not be in unison, but that when one of the pairs of bars ismoving forwardly, another of the pairs will be moving rearwardly. Thismovement will be hereinafter referred to as an alternate movement.

When the herein described straw-burning furnace is used in connectionwith a traction engine, straw may be passed over platform 27 and reachesfire-box 3 through opening 7. To assist in causing uniformity ofconsumption, I provide certain devices to be considered in connectionwith draftopening 2S; this opening is preferably located below orsomewhat lower than platform 27, and is at the lowest part of thefire-box and is useful for removal of refuse as well as an aid tocombustion, as will be presently described.

From the description it will be seen that the grate-bars, duringoperation, have movements in pairs; they are raised and lowered inalternation and these movements facilitate combustion of the bed ofstraw thereon, since air may circulate between the raised and loweredparts. The operation of the pawl and ratchet already described, causesintermittent rotary movements of crank shafts 12 and 13, this being adesired feature; the interruption in the rotary movements of theseshafts causes vibration of the fuel upon the grate-bars which aids incombustion, and in operation a limited speed is all that is required.

I provide a carrier or means for removing ashes and non-combustiblematter from the fire-box, consisting of the fieXible members or sprocketchains 29 mounted upon pulleys 30 and 31 and having, at suitableintervals, the Scrapers or bars 30 secured crosswise thereon. Pulleys 30are rigidly mounted upon shaft 32, at the front of the fire box, pulleys31 being rigidly mounted upon shaft 33 within and near the rear end ofsaid fire box. Shaft 32 may be actuated by the flexible member or belt811, mounted upon pulleys 35 and 36, these pulleys being mounted,respectively, upon shafts 22 and 82, and in operation, if shaft 22 isrotated in the direction indicated by the arrow in the drawing, ashes orother matter falling upon the bottom 37 of the fire box will be movedforwardly by the Scrapers, and may be deposited in ash receptacle 38.

In practice, any partly burned straw which falls downward between thepairs of grate-bars 9, 10 and 11, will be readily consumed in that partof the fire boX near draft opening 28, and the metallic apron 18prevents movements of the flames in this part of the furnace from beingdirected upon fuel at intake 7 until the newly added fuel is movedrearwardly from the grate-bars.

The conditions met with in burning straw are so different from thoseexisting in the consumption of coal or like fuel, that the same methodscan not be employed in both cases. The compactness of straw and thelarge quantity of ashes left when it is burned, demand that a plentifulsupply of air be supplied to the seat of combustion if the best resultsare to be obtained. The wide spaces left by mounting the bars in spacedpairs permits the ready escape of the ash and the ready access of air tothe burning straw. In addition to this the alternate walking movement ofthe pairs of bars continuously shifts the body of burning straw from oneangle to another, thereby opening fresh air spaces Vtherethrough andtending to separate the straw.

In the use of the herein described furnace, power can, in most cases, beconveniently obtained for moving the ash-rake and gratebars, and asingle operator is sufficient for managing the same. The devices may beemployed and the parts may be placed in furnaces already built in manyinstances, only slight changes being required for the mounting thereinof the parts which have been mentioned.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent is,-

1. In a straw burning furnace, the combination with a continuouslyrotating driving member, of a crank sha-ft having a plurality of cranksset at varying angles thereto, a plurality of grate bars mountedlongitudinally of the furnace and in pairs, said grate bars beingengaged by the crank shaft and said pairs being spaced from each other aconsiderably greater distance than the distance between the bars of eachpair, the connection of the grate bars with the crank shaft serving toimpart a walking movement to said bars, the movement of the bars of apair being in unison, but the movement of said pairs of bars beingalternate, an ash pit beneath said bars having an open rear end and aclosed bottom, a rearwardly moving scraper traveling over the floor ofsaid ash pit, connections between the driving member and the scraper, aswinging arm, a

pawl and ratchet connection between said arm and said crank shaft, and aconnection between said swinging arm and said driving member whereby themovement of the crank shaft is rendered an intermittent one.

2. In a straw burning furnace, the combination with a plurality of gratebars mounted in pairs, said pairs being spaced from each other aconsiderably greater distance than the distance between the bars of eachpair, of means for imparting a walking movement to said grate bars, themovement of the two bars of a pair being in unison, but the movement ofsaid pairs being alternate.

3. In a straw burning furnace, the combination with a plurality of gratebars mounted in pairs, said pairs being spaced from each other aconsiderably greater distance than the distance between the bars of eachpair, of means for imparting a walking movement to said grate bars, themovement of the two bars o a pair being in unison, but the movement ofsaid pairs being alternate and intermittent.

4. In a straw burning furnace, the combination with a plurality of gratebars mounted in pairs, said pairs being spaced from each other aconsiderably greater distance than the' distance between the bars ofeach pair, of means :for imparting a walking movement to said gratebars, an ash pit beneath said bars having an open rear end and a closedbottom, and a rearwardly moving scraper traveling over the iioor of saidash pit to remove the ash from the straw burned on the grates.

5. In a straw burning furnace, the combination with a plurality of gratebars mounted in pairs, said pairs being spaced from each other aconsiderably greater distance than the distance between the bars of eachpair, of means for imparting a walking movement to said grate bars, anash pit beneath said bars having an open rear end and a closed bottom,and a rearwardly moving scraper traveling over the floor of said ash pitto remove the ash from the straw burned on the grates, said scrapercomprising an endless belt and a plurality of scraper blades carriedthereby.

In testimony whereof I have affixed my signature in presence of twowitnesses.

ANDREW G. JOHNSON.

Witnesses:

JOHN ALLEN, M. L. KLINTBERG.

